fix(sw): align header logo styles and refine viewer UI

src/sw/sw-viewer-fixture.tsx

@@ -6,6 +6,11 @@ import {
   type SWHeaderDocument, type SWViewerCommand, type SWViewerHeaderGroup, type SWViewerHeaderProps, type SWViewerPanelProps,
 } from "@hm-design/sw"
 import { Info, Layers, List, MousePointerClick, RotateCcw, Scan, SlidersHorizontal, ZoomIn } from "lucide-react"
+import placeholderLogo from "./assets/sw-header-logo-placeholder.svg"
+
+// 2026-10-23: the regular viewer Stories show the TEMPORARY placeholder logo of the SW Header Stories (not a product
+// logo); only SW/Viewer › Logo › 로고 없음 renders without one.
+export const VIEWER_STORY_LOGO = { logoSrc: placeholderLogo, logoAlt: "임시 로고" } satisfies Partial<SWViewerHeaderProps>
 
 export const SAMPLES = [
   { id: "sample-basic", label: "기본 도면 · DWG", name: "BasicSample.dwg" },